In this paper, a low-cost patch antenna with circular polarization using a FR4 substrate is proposed. The antenna was developed to be used in US standard UHF RFID application, with better impedance matching at 915MHz. The design was concepted and optimized through simulations using the ANSYS HFSS software. The simulation results presented an absolute gain of 5.76dB, an axial ratio of 1.87dB and the return loss (S11) of 48dB at 915MHz. The antenna was manufactured and measurements of the return loss using the Keysight Vector Network Analyzer were made to compare with the simulation results. Furthermore, it was compared to a commercial antenna by reading a commercial tag using a RFID reader in order to validate the proposed antenna application.